1. Field of the Invention
The present invention relates to a key switch device having a guide member provided with two link members mutually rotatably disposed, one link member being supported at an upper end thereof with respect to an underside of a key top and at a lower end thereof to a support plate and the other link member being supported at an upper end thereof to the underside of the key top and a lower end thereof to the support plate, the guide member functioning of guiding vertical movement of the key top to thereby effect a switching operation. In particular, the present invention relates to a key switch device having mounting members for movably supporting the lower ends of the link members respectively, the mounting members being fixed on the support plate by a predetermined fixing manner, which can reduce manufacturing cost of the support plate and increase design flexibility of a keyboard provided with a plurality of the key switch devices.
Furthermore, the present invention relates to a key switch device having a film sheet for performing a switching operation, the film sheet being disposed below a key top, and mounting members for movably supporting each lower end of two link members of a guide member, the mounting members being fixed on the film sheet, which can reduce manufacturing cost and increase design flexibility of a keyboard provided with a plurality of the key switch device, and achieve weight reduction of the keyboard.
Furthermore, the present invention relates to a portable electronic device provided with a keyboard on which a plurality of key switch devices are arranged and a sheet-type secondary battery, and particularly to a portable electronic device capable of facilitating the design and manufacture thereof and improving the reliability.
2. Description of Related Art
Conventionally, there have been proposed key switch devices each having a guide member constructed of a pair of link members mutually movably connected in an intersecting state, and the guide member serves to guide the vertical movement of a key top to effect a switching operation in association with the vertical movement of the key top. For example, such a key switch is disclosed in Japanese utility model application laid-open No. Hei 2-5236. This key switch is provided with a key top, an upper holder attached to an underside of the key top, a first lower holder and a second lower holder attached to a printed substrate, and two rectangular frames connected to each other in an X-shaped configuration as viewed in side elevation, which is disposed between the key top and the printed substrate.
In this key switch, an upper portion of one of the rectangular frames is slidably supported in the upper holder between the lower surface of the key top and the upper holder, while leg portions of the rectangular frame are rotatably supported in the first holder. On the other hand, an upper portion of the other rectangular frame is rotatably supported in a groove of the upper holder, while leg portions of the rectangular frame are slidably supported in the second holder. Furthermore, a rubber switch is disposed on the printed substrate, and a convex portion of the key top, projecting downward, is engaged with the rubber switch. The rubber switch is provided with a movable contact disposed corresponding to a fixed contact disposed on the printed substrate.
The above key switch is configured such that the key top is vertically moved with its horizontal position being maintained, no matter which portion of the key top is depressed by an operator. Accordingly, the movable contact of the rubber switch engaged with the key top is made into contact with the fixed contact of the printed substrate whenever the rubber switch is pushed upon depression of the key top, thus effecting a switching operation.
However, in the above key switch disclosed in Japanese utility model application laid-open publication No. Hei 2-5236, the first and second lower holders attached to the printed substrate are all inserted in mounting holes formed in the printed substrate (see FIGS. 2 and 4 in the publication) and fixed therein. Therefore, each lower end of the first and second lower holders is made projecting downward from a lower surface of the printed substrate.
Such projecting lower ends of the first and second lower holders may cause a difficulty in thickness reduction of the key switch and be against actual circumstances that the reduction of the thickness of a key switch is promoted.
To conform the need of reduction in size and thickness of a keyboard with a sufficient key stroke being ensured, applicant of the present invention proposed a key switch device which is disclosed in U.S. Pat. No. 5,50 283, in which an electrical circuit pattern is formed on an insulating layer provided on a metal substrate, and four mounting portions are formed integrally with the substrate by pressing and disposed surrounding a fixed contact pattern in the circuit pattern. Two of the four mounting portions are used as rotatably supporting portions, and the other two are used as slidably supporting portions.
In the above switch device, a guide supporting member constructed of two link members which are mutually rotatably connected is disposed between the key top and the substrate. A support shaft formed at an upper end of one of the link members is rotatably supported in the connecting portion formed on the underside of the key top and a support pin formed at a lower end of the link member is slidably supported in the slidably supporting portion of the substrate. A support pin formed at an upper end of the other link member is slidably supported in the connecting portion formed on the underside of the key top and a support shaft formed at a lower end of the link member is rotatably supported in the rotatably supporting portion of the substrate.
In the key switch disclosed in the U.S. Pat. No. 5,504,283, the metal substrate is formed integrally with the mounting portions (supporting portions) by pressing, the mounting portions serving to slidably or rotatably support the support pins or shafts disposed on the lower parts of the link members. Thus, this realizes a key switch device which can ensure a sufficient key stroke and reduce the size of the keyboard, especially the thickness thereof.
However, a predetermined pressing work to integrally form the mounting portions with the substrate needs a relatively large pressing die in order to form the mounting portions in the whole area of the substrate. Since the pressing die is expensive, the cost of the key switch device is increased in association therewith.
Furthermore, specifications such as the placement manner of key switches are generally determined in respective countries. If the key switch device is manufactured based on the specifications in the countries where the key switch device is to be used, plural types of a pressing die must be prepared to perform a suitable pressing work on a substrate in response to the respective specifications. Accordingly, the preparation of plural pressing dies, each being inherently expensive in cost, may cause the increase in cost of the key switch device.
Furthermore, the metal substrate itself used in the above key switch device is considerably heavy, so that the whole key switch device increases in weight. This obstructs weight reduction of the key switch device.
Meanwhile, there has also been known a portable electronic device, such as a notebook-size personal computer and the like, provided with the above key switch devices and a secondary battery which is rechargeable plural times and is built-in a main unit of the electronic device. When the secondary battery is charged in advance from an exterior power source, the electronic device can work on the secondary battery even in a place or area where the power supply from the exterior power source is impossible. Due to the shape, weight, thickness, etc. of the secondary battery, however, the secondary battery often had a disadvantageous effect on the portability and shape of the electronic device.
One type of the electronic device provided with the secondary battery is shown in FIG. 40. A secondary battery 239, attached to the internal bottom of an electronic device 240 such as a notebook-size personal computer, supplies necessary electricity to the electronic device 240 even when the electronic device 240 is used in a place where power supply from an exterior power source is impossible. As the secondary battery 239, various type shaving different shapes, weight, thickness are known. It is generally considered very large in thickness and weight.
In this way, since the electronic device 240 is provided with the secondary battery 239 which is selected from various types having different shapes, weight, thickness, etc., a designer has to design the electronic device 240 in consideration of the shape, weight, thickness, etc. of the secondary battery 239 in addition to the internal structure of the electronic device 240. This may impose a burdensome work on the designer or take much time to develop the electronic device 240.
Depending on the shape, thickness, and others of the secondary battery 239, sufficient heat radiation can not be carried out against the heat generated in the secondary battery 239 when charged from the exterior power source. Due to this insufficient heat radiation, the electronic device 240 may rise in temperature.
Because of the weight and the attachment position of the secondary battery 239, furthermore, the electronic device 240 loses its center of balance, which may cause damage to the portability of the electronic device 240.